A.
anwered by: canteau
SRAM brakes will have a little more clearance that the Ultegra which has an official capacity of 25mm but should fit a 28mm tire on most rims. The Shimano 105 5800 brakes are rated at 28mm and are more inline with the SRAM brakes as far as width goes.
Both the 105 and Ultegra brakes use Shimano's SLR pull ratio which will give a more positive lever feel when used with newer Shimano STI levers.